Communicating is often difficult, and even virtually impossible, for the physically impaired. Speech impairment may prevent audible communication, for example, while further lack of muscle control may prevent communicating data or commands to a machine, such as a computer. In many cases, the physically impaired person is able to do little more than breathe, and an otherwise active and functional mind is excluded from interaction with his or her environment.
Of the various existing communication aids available for generating an output information message in a desired format, those called single switch devices are designed to be used by anyone who can manage to operate a single switch. Scanning devices are one example. Such a device employs a two dimensional matrix of illuminated cells, each cell containing a letter, number, word, or phrase for the operator to select.
The device sequentially selects one row of the matrix at a time, by illuminating all the elements in each row. The operator presses a switch to select an illuminated row, and the scanning then begins to cycle between the various cells in the selected row, illuminating them sequentially one at a time. A second switch closure is used to select the desired cell in the row. By this technique, an information message can be generated by the manipulation of a single switch.
Although enabling an operator to display a selected character combination, this method has certain drawbacks. Firstly, it is slow since the entire matrix must be scanned to reach a particular cell. Secondly, the anticipation and reaction time required to press the switch at just the right moment, can be difficult, especially to a physically impaired operator. Thirdly, the apparatus is usually bulky and expensive, and thus confines its use to classroom or therapy situations. Thus, another means of communicating with a single switch device is desirable, both for the physically impaired and other operators desirous of using a single switch input.
The Morse Code is also employed by those who are physically handicapped. For example, a Morse Code computer translator, such as the Adaptive Firmware Card, can be purchased from Adaptive Peripherals, of Seattle, WA., may be employed by those only able to use a single switch. Since such a translator device is adapted to be used with conventional computers, it is capable of being used only with a particular computer model, and the size and power requirements of the computer and peripheral card, make portability difficult. Also, the cost for purchasing such equipment prohibits wide spread use for the physically impaired.
In the Morse Code, which is inherently a "single-switch" code, letters, numbers, and punctuation elements are formed by groups of short and long switch closures, called dots and dashes. However, reasonable skill is required to form the properly timed sequence of dots, dashes, and spaces in between, to form the Morse Code characters. Such rhythmical manipulation is often beyond the ability of uninitiated operators, and especially many physically impaired operators.
The rhythm of the Morse Code requires time and coordination to learn. For some, it is virtually impossible to release the switch for the proper length of time to form the spaces between the dots and dashes. An even more difficult task is the formation of the longer spaces between characters. Varying sending speeds, that often characterize a novice operator, introduces character ambiguities, such as three fast letter "T's", which have the same relative timing as a slow letter "S".
Thus, it would be desirable to have a device that overcomes the difficulties associated with forming the carefully timed sequences of dots, dashes, and spaces of the Morse Code or similar on-off character code, so that a physically impaired person could somehow make use of the Morse Code for communication purposes. Also, it would be well to have such a device that would be relatively inexpensive to manufacture, and be very light in weight and small in size for portability.